Why set zfs mountpoint to legacy
It uses zfs datasets created on the global zone and shared with lofs as set up by a supplier.
During my research I found an article that if you are sharing zfs datasets with non-global zones you must set :
zfs set mountpoint=legacy
I have checked the properties on the datasets which the non-global zone uses for eg. server1-root/rpool and server-data/u01.
These all seem to be set to default still rather than set to legacy.